This invention relates to polymeric films. More particularly, the invention concerns polymeric films having properties that make the film useful for cling wrap film, such as that used for wrapping pallet loads of various materials.
Known polymeric materials used for cling (also known as stretch) wrapping of palletized loads include polyvinyl chloride, polyethylene, and ethylene-vinyl acetate copolymers. U.S. Pat. No. 4,222,913 teaches the use of a three-component blend for cling wrap formulations, the components being an ethylene-vinyl acetate copolymer as the base resin, a polypropylene copolymer added to achieve a thin film gauge, and a third component as a tackifier. The patent teaches that the ethylene-vinyl acetate and the polypropylene copolymers should have similar viscosities (for compatibility during blending) and refractive indices (for optical properties). The low molecular weight tackifier tends to bloom to the surface, giving the necessary cling properties.
Prior 2-component systems, such as low density polyethylene base resin and a glyceryl mono-oleate tackifier, show easy processing, but they typically have a low tackiness, with the tackiness failing at temperatues below about 40.degree. F., leading to storage and customer use problems.
It is an object of this invention to produce a 2-component cling film composition that overcomes at least a majority of these deficiencies.